Photosynthesis is a biological process by which energy contained within light is converted into chemical energy of bonds between atoms that power processes within cells. Photosynthesis is a process of taking inorganic material to make their proper organic materials through the combining of carbon dioxide and water using solar energy. This process only occurs in green plants, blue-green algae, and certain bacteria. The chlorophyllic leaf captures light energy that is necessary for processing the synthesis of organic material. This leaf contains chlorophyllic cells which have green organelles called chloroplasts containing chlorophyll. The chloroplasts form a real “factory”. The conversion of light into chemical energy and the storing of sugar helps plants grow and mature. The first organic molecules synthesized during photosynthesis are the carbohydrates which accumulate in the form of complex molecules called starch. The starch that is synthesized in the leaf during the day is hydrolysed at night. The presence of starch can be easily detected by iodine water that shows a violet blue coloration. The production of organic materials is accompanied by the release of oxygen that is easily evidence in aquatic chlorophyllic plants. The release of oxygen and the absorption of carbon dioxide by photosynthesis mask the respiratory gas exchange in a green plant. (Jamm, Dagher, Ghorayeb, & Hajjar, 1999)
What are the necessary conditions for photosynthesis to take place?
hawraa: carbon dioxide, chlorophyll, and light.
Alia Olivia: CO2, Chlorophyll and light. Samia El Kurdi: Carbon Dioxide, Chlorophyll, and light.
How can starch synthesis in green leaves be proved when exposed to sunlight?
hawraa: by using iodine test, where a violet blue color indicates a positive test and thus presence of starch.
Alia Olivia: Test using iodine. Indication of presence of starch is a change of color to violet.
Samia El Kurdi: To prove starch synthesis in green leaves when exposed to sunlight you should apply iodine test. If a violet blue color is produced then this indicates the presence of starch.
A leaf collected in the morning before it is exposed to sunlight, has the same color as a leaf placed in darkness. Formulate a hypothesis to explain the absence of starch in the leaf collected at the morning.
hawraa:the hypothesis is that the collected leaf has consumed all the starch that it already formulated the day before, and at night there is no light for photosynthesis to take place, so we have abscence of starch in the next morning, on the other hand, the leaf present in darkness will never undego photosynthesis and thus no starch is present.
Alia Olivia: The leaf present in the absence of light will never form starch meaning it will not undergo photosynthesis.
Samia El Kurdi: My hypothesis is that the leaf in the morning undergoes photosynthesis because it was exposed to light while the other leaf did not undergo photosynthesis since there is no light which is an important factor for achieving the process of photosynthesis. Therefore, no starch is present in the leaf located in darkness.
References:
Jammal, N, Dagher, J, Ghorayeb, L, & Hajjar, Z. (1999). Life science first year secondary. Sin-El-Fil, Lebanon: national center for research and pedagogical development.
Photosynthesis is a biological process by which energy contained within light is converted into chemical energy of bonds between atoms that power processes within cells. Photosynthesis is a process of taking inorganic material to make their proper organic materials through the combining of carbon dioxide and water using solar energy. This process only occurs in green plants, blue-green algae, and certain bacteria. The chlorophyllic leaf captures light energy that is necessary for processing the synthesis of organic material. This leaf contains chlorophyllic cells which have green organelles called chloroplasts containing chlorophyll. The chloroplasts form a real “factory”. The conversion of light into chemical energy and the storing of sugar helps plants grow and mature. The first organic molecules synthesized during photosynthesis are the carbohydrates which accumulate in the form of complex molecules called starch. The starch that is synthesized in the leaf during the day is hydrolysed at night. The presence of starch can be easily detected by iodine water that shows a violet blue coloration. The production of organic materials is accompanied by the release of oxygen that is easily evidence in aquatic chlorophyllic plants. The release of oxygen and the absorption of carbon dioxide by photosynthesis mask the respiratory gas exchange in a green plant. (Jamm, Dagher, Ghorayeb, & Hajjar, 1999)
What are the necessary conditions for photosynthesis to take place?
hawraa: carbon dioxide, chlorophyll, and light.
Alia Olivia: CO2, Chlorophyll and light.Samia El Kurdi:
Carbon Dioxide, Chlorophyll, and light.
How can starch synthesis in green leaves be proved when exposed to sunlight?
hawraa: by using iodine test, where a violet blue color indicates a positive test and thus presence of starch.
Alia Olivia: Test using iodine. Indication of presence of starch is a change of color to violet.
Samia El Kurdi:To prove starch synthesis in green leaves when exposed to sunlight you should apply iodine test. If a violet blue color is produced then this indicates the presence of starch.
A leaf collected in the morning before it is exposed to sunlight, has the same color as a leaf placed in darkness. Formulate a hypothesis to explain the absence of starch in the leaf collected at the morning.
Alia Olivia: The leaf present in the absence of light will never form starch meaning it will not undergo photosynthesis.
My hypothesis is that the leaf in the morning undergoes photosynthesis because it was exposed to light while the other leaf did not undergo photosynthesis since there is no light which is an important factor for achieving the process of photosynthesis. Therefore, no starch is present in the leaf located in darkness.
References:
Jammal, N, Dagher, J, Ghorayeb, L, & Hajjar, Z. (1999). Life science first year secondary. Sin-El-Fil, Lebanon: national center for research and pedagogical development.
Photosynthesis reactions. [Web]. Retrieved from http://www.water-research.net/images/phosyn.GIF
The process of photosynthesis. (2003). [Web]. Retrieved from http://ellerbruch.nmu.edu/../pics/photosynthesis.jpg